1. Field of the Invention
The present invention relates to a non-contact IC label and a nameplate used in a UHF band and an SHF band.
2. Description of Related Art
Exchange of information using wireless communication has been conventionally performed between an RFID tag (a non-contact IC label) and a reader (a data reading device). However, when this RFID tag is attached to a metallic adherend, communication performance is degraded.
Further, conventionally, an RFID (Radio Frequency IDentification) tag is generally embedded in a body portion of a nameplate configured to be able to communicate with, for example, a data reading device in a non-contact manner. Further, the nameplate cited herein refers to an object in which a brand (specification) is displayed in, for example, a plate. Even when this nameplate is directly attached to the metallic adherend, the communication performance of the RFID tag is degraded.
In order to resolve this problem, configurations of various RFID tags, as will be described hereinafter, have been examined.
For example, in an RFID tag of an electromagnetic induction system using radio waves in a 13.56 MHz band, a magnetic material (a magnetic sheet) with high permeability is provided between an antenna and an adherend to secure a low loss route of magnetic flux between the antenna and the adherend, thus realizing an RFID tag capable of maintaining communication performance even when attached to the metallic adherend. Further, although the communication performance is degraded, the thickness of the magnetic material can be made as small as, for example, 100 μm or less. Accordingly, a thin metal-compliant RFID tag corresponding to the metallic adherend can be produced.
On the other hand, in an RFID tag of a radio wave system used in a UHF band and an SHF band, a method of providing a dielectric or an air layer between an antenna and an adherend to secure a gap between the antenna and the adherend and suppress influence of the adherend is generally used.
However, in this method, when a dielectric having a thickness of approximately 500 μm is used or an air layer having such a thickness is provided between the antenna and the adherend, an interval between the antenna and the adherend is too small. Accordingly, influence of the metallic adherend is strong and communication cannot be performed. Accordingly, at present, it is difficult to produce a thin (500 μm or less thick) RFID tag used in a 13.56 MHz band.
As another RFID tag of a radio wave system used in a UHF band and an SHF band, a configuration in which a magnetic material is provided between an antenna and an adherend is proposed (for example, see Japanese Unexamined Patent Application, First Publication No. 2005-309811). In this RFID tag, a soft magnetic material is arranged between the antenna and the metallic adherend. In Japanese Unexamined Patent Application, First Publication No. 2005-309811, the soft magnetic material is clearly described. On the other hand, there is only a description of a dipole antenna and its modified antenna as the used antenna. Further, even in actual verification, there is no detailed description of a shape of the antenna. Only an example in which a thickness of the magnetic material is 1 mm (the communication distance is 15 mm) is described.
However, in the above-described RFID tag of the radio wave system used in the UHF band and the SHF band, there is a problem in that, for example, when the RFID tag is used as a label, the label is too thick and is not practical.
In a general RFID tag, a width of the antenna is typically 1 mm or less. Further, in some RFID tags, a meander shape with a small antenna width has been adopted for miniaturization and a high antenna gain. It was found from an experiment conducted by the inventor that, when the RFID tag described in Patent Literature 1 above includes the general antenna as described above, sufficient communication performance cannot be obtained simply by making the soft magnetic material thin.
Further, an IC chip used in Patent Literature 1 above and the other non-contact IC label described above has a property of the IC chip being very easily broken because it is formed of monocrystalline silicon. Here, for example, when this non-contact IC label is adhered to a hard adherend (a metallic object such as a car), it is difficult for the adherend to absorb external shock due to sinking or the like. Further, when the thickness of the non-contact IC label is small, a part of the non-contact IC label that absorbs the shock in a thickness direction and buffers against the shock is small. Accordingly, there is a problem in that the IC chip in the non-contact IC label is easily broken due to external stress or shock.
Further, in the above-described RFID tag of the radio wave system used in the UHF band and the SHF band, there is a problem in that, for example, when this RFID tag is embedded in a nameplate, the nameplate is too thick and is not practical. Further, for use as a nameplate, it is desirable for the nameplate to be small in order to make handling easier.
In order to miniaturize the nameplate, an antenna having a width of 1 mm or less is typically used as an antenna of the RFID tag. It was found from the experiment conducted by the inventor that, when the RFID tag described in Patent Literature 1 includes a normal antenna, sufficient communication performance cannot be obtained simply by making the soft magnetic material thin.
The present invention has been made in view of such problems, an object of the present invention is to provide a non-contact IC label and a nameplate having a structure that is used with radio waves of a UHF band and an SHF band, has a thin and small form capable of communication even when attached to a metallic adherend, and is capable of withstanding external stress and impulsive force.